It’s exam time. Drink up. Your brain is almost 75% water. Stay hydrated. The math is pretty easy – even for art majors. We all know how important hydration is when engaged in physical activity; the same is true for mental activity. This important aspect of staying healthy and hydrated is often overlooked.

Dehydration can take a major toll on your body (even mild dehydration can slow down your metabolism by as much as 3%). It also impacts the brain.

When you are dehydrated, the cells in your brain wither and shrink, promoting mental lethargy – not a good head space for exam taking. Dehydration impairs brain function by reducing your working memory. Here is how Wikipedia defines working memory: “the system that actively holds multiple pieces of transitory information in the mind, where they can be manipulated.” Even slight dehydration can impede the performance of cognitive tasks.

Some literature suggests that as many as 75% of Americans are chronically dehydrated, a condition that can cause digestive problems, kidney stones, depression, and cancer of the bladder, prostate and kidney. Even mild dehydration can have deleterious effects like fatigue, general grumpiness, back pain, joint pain, short-term memory loss, tension, and anxiety. Overeating can also be triggered by dehydration, as hunger is often confused with thirst.

Sweat, tears, exertion, elimination, and even respiration all contribute to dehydration. Even if you are just sitting there thinking, your body is using up its water resources. It adds up over time. Dehydration effects your mood, your thoughts, your brain, and even your looks.

So how much do we need to drink to get through exams? The Mayo Clinic recommends “that an adequate intake (AI) for men is roughly 3 liters (about 13 cups) of total beverages a day. The AI for women is 2.2 liters (about 9 cups) of total beverages a day.” (http://www.mayoclinic.org/healthy-living/nutrition-and-healthy-eating/in-depth/water/art-20044256)